DNS-over-HTTPS (DoH) Support in Mozilla Firefox
Recent releases of Firefox have introduced the concept of DNS privacy under the name “Trusted Recursive Resolver”. Although Firefox ships with DNS-over-HTTPS (DoH) disabled by default, there has been some discussion within the Mozilla developer community about changing the default to “enabled”.
Although DoH is somewhat controversial because it moves control plane (signalling) messages to the data plane (data forwarding), and can thereby bypass local network policies, DoH advocates argue that it makes it harder to block or monitor DNS queries which is a commonly used method for restricting access to the Internet and/or monitoring user behaviour.
But putting these arguments aside, if you want to try out DoH then the DNS privacy (or “TRR” in Firefox speak) configuration in Firefox can be accessed as follows:
- Enter “about:config” in the address box of the browser
- Search for “trr” (without quotes)
A sample output of DNS privacy configuration in Mozilla Firefox is as follows:
Firefox offers its technical users quite a few settings to play with, but the most important options (along with their recommended settings) for TRR are:
- trr.bootstrapAddress:(empty)
- trr.mode: 3
- trr.uri: https://mozilla.cloudflare-dns.com/dns-query
“network.trr.bootstrapAddress” specifies the IP address of a recursive resolver that should Continue reading













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